The Papal Basilica of Santa Maria Maggiore in Rome is one of the city’s four papal basilicas and a UNESCO World Heritage Site. As a major pilgrimage destination, it hosts a range of services and events, from daily masses to papal celebrations that are broadcast around the globe. These activities demand an audio solution that is capable of delivering clear and intelligible speech across vast, reverberant spaces, whilst also remaining discreet in the highly protected surroundings.
In 2018, AV integration specialists, Delta Tecno Studio, completed a full redesign of the basilica’s audio system, replacing an outdated infrastructure with a Q-Sys-based network and K-array’s column array loudspeakers in the main worship areas. This system, which was awarded a 2019 InAVation Award, resolved long-standing challenges around speech intelligibility and coverage, and introduced a custom, user-friendly interface allowing the clergy to easily operate the audio system across several zones. In 2025, the Delta Tecno Studio team returned to the basilica to expand the K-array audio system into four side chapels, spaces that serve a central role in the daily rhythm of prayer and worship at the basilica.
With many years of experience working in sensitive environments, Delta Tecno Studio understand the importance of respecting heritage spaces and their acoustic characteristics. Working in collaboration with consultant and owner of Delta Tecno Studio, Dario Zanotti, and sound system designer, Pier Luigi Pecchenini, Pietro Radaelli and Emanuele Zanotti were already established as trusted technology partners of the basilica.
“Following the completion of the main project in 2018, the priests at the basilica have enjoyed the flexible, clear and easy-to-use audio system, allowing them to focus on their liturgy rather than struggling with audio coverage or microphone issues,” explains Emanuele Zanotti at Delta Tecno Studio. “The success of this project has led to the recent expansion into four lateral chapels and the integration of the audio in these chapels with the overall central system.” The relationship with the basilica has been ongoing since 2018, with Delta Tecno Studio maintaining and optimising the existing system over the years.
The latest phase of the project focused on incorporating the four chapels and maintaining identical audio quality and consistency. This included consistency in the user experience, with simple preset-based operation from a touchscreen in the sacristy, or via wireless devices through a dedicated network. Ensuring the infrastructure is fit for future expansions and has robust redundancy built in was another essential requirement.
“The goal was extension and unification,” confirms Pietro Radaelli at Delta Tecno Studio. “The basilica wanted one integrated system, not separate subsystems. From the user’s perspective, it had to remain simple, whether they were activating the full church or just the chapels, depending on the service or event.”
Whilst the nave and altar host the largest celebrations, the chapels are critical for daily operations. They are often used for small weekday services, private prayer and devotional gatherings. This meant that speech intelligibility was high on the list of requirements. Visitors and clergy needed the same high level of audio clarity in these smaller, more intimate spaces as in the central basilica.
The expansion followed the same design philosophy as the original project: a fully digital audio distribution network, using QSC’s Q-SYS platform for DSP and control, with signals transported over fibre and Cat 6 cable. Two of the chapels, Cesi and Sforza, are equipped with pairs of 0.5-metre K-array Kobra KK52 column loudspeakers. In the most architecturally sensitive areas, such as in the Cappella Paolina, four KK52 are coupled into two small arrays, with two additional ultra-mini, gold-coloured Lyzard loudspeakers installed to provide discreet sound reinforcement for the seats to the side of the altar. In the Cappella Sistina, two additional Vyper KV52 loudspeakers provide extra coverage in combination with the half-metre Kobra units.
The narrow vertical dispersion and long throw achieved by the array configuration of K-array’s solutions helped to overcome the challenges of these highly reverberant spaces, whilst requiring fewer loudspeakers overall, reducing visual distractions. The slim profile of K-array’s solutions is another benefit, and by staying within the same loudspeaker families as the existing main basilica system, consistency was guaranteed across the entire site.
“We are very familiar with K-array products, and thanks to their particular characteristics and features, when coupled with careful configuration, you don’t need many loudspeakers to achieve excellent coverage,” continues Radaelli. “With a proper combination of loudspeakers, aiming and tuning, you can very clearly hear intelligible speech without energy wasted in reverberation.”
Following the same methodology as the 2018 project, extensive EASE modelling was carried out to predict coverage and intelligibility, followed by on-site testing with real-time acoustic analysers. “A preliminary acoustic survey and instrumental measurement session was conducted with our in-house acoustic engineer, Davide Squarciapino,” explains Radaelli. “A precise and accurate acoustic assessment of the rooms allowed us to perfectly calibrate a three-dimensional mathematical-physical model used for electroacoustic simulations, allowing us to verify the real suitability of the selected K-array solution.”
Delay and equalisation were specially programmed for each loudspeaker, and presets were created for common scenarios, such as chapels operating individually, together or in combination with the central nave.
“During services or events, the priests can quickly set up the system,” says Zanotti. “They just press the buttons related to the area or service they are giving, and the system reconfigures automatically.”
The chapels are connected via fibre back to the sacristy, where amplification and processing are centralised. Q-Sys power amplifiers drive the K-array loudspeakers, with full DSP capability for each output channel. Dante converters were included to allow for the integration of future microphones or additional loudspeakers.
The physical installation was carefully managed to reduce any impact on the fabric of the building. Existing loudspeaker mounting points were reused where possible, and cabling followed the architectural lines of the chapels, fixed with specialist adhesives to avoid damaging surfaces. The Delta Tecno Studio team also installed a new Wi-Fi network to allow for remote access to the system.
“As one of the oldest churches in the world, the walls and architecture are strictly protected,” notes Radaelli. “Every fixture and every cable route must be justified. By using the slimline K-array enclosures together with the custom mounting systems we engineered, we avoided the need for any intrusive fixtures, which is a major advantage.”
Controlled audio directivity and careful loudspeaker alignment helped to minimise reverberation, whilst cabling was installed carefully using non-invasive methods to protect the historic building. QSYS and Dante integration provides the flexibility for chapels to operate either independently or as part of the main system. A dedicated manual mode was specially developed to allow Vatican Radio technicians to take direct control and use their own equipment, such as microphones, with the main system during papal events. Furthermore, a fully hardware redundant DSP solution ensures services are never interrupted.
The new system expansion provides high-quality, clear audio coverage across the four chapels, unified with the rest of the basilica under a single, intuitive user interface. Clergy can operate the entire system without technical expertise, and technicians have full access for advanced configuration and monitoring.
“The priests tell us that hearing clearly is more important than seeing for worshippers,” concludes Zanotti. “We have worked hard to successfully implement a system that ensures that every word is intelligible, across all spaces in the basilica.” The expanded system at the Santa Maria Maggiore, installed with expertise and care by the Delta Tecno team, proves that technology can serve both function and faith in harmony.
